#include <57header.h>


int main(int argc,char*argv[])
{

    sigset_t set, old;
    sigemptyset(&set);
    sigemptyset(&old);
    
    sigaddset(&set, 2);
    
    sigprocmask(SIG_BLOCK, &set,  &old);

    sleep(5);

    sigset_t pending;
    sigemptyset(&pending);
    sigpending(&pending);

    if(sigismember(&pending, 2)){
        printf("2号信号未决 \n");
    }

    sigprocmask(SIG_UNBLOCK, &set, &old);


    while(1);
    return 0;
}

